The present invention relates to an electromagnetic relay characterized by the manner in which a coil lead for the electromagnet is connected to terminals through which the coil lead is connected in turn to, e.g., an external circuit.
A conventional electromagnetic relay has an arrangement such as that shown in Japanese Utility Model Unexamined Publication No. 55-111142, in which the coil lead is connected to terminal portions of the base by winding the end portions of the coil lead around the terminal portions, thereby connecting and fixing the coil lead to the terminal portions. Another method of connecting these members is shown in FIG. 3, in which junction terminals fixed to the coil bobbin are employed. During the winding process, the coil lead is connected to the junction terminals, and, after the entire coil section has been fixed to the base supporting terminals for establishing external connection, the junction terminals and the external-connection terminals are connected for electrical connection by, e.g., a welding method. Specifically, referring to FIG. 3, the device includes a terminal 1 through which a coil lead is connected to an external circuit, a junction terminal 2a for the coil lead, a coil 11 for the electromagnet, a connecting portion 2b of the coil lead, a coil bobbin 7, stationary terminals 15 and 16, a yoke 8, a core (iron core) 14, a plate 17, a spring 18a, a base 12, and a casing 13. The coil lead junction terminal 2a is fixed to the coil bobbin 7, and, during a winding process, the connecting portion 2b of the coil lead is wound around the junction terminal 2a, as shown in the figure, and is then connected thereto by means of solder or the like. Thereafter, when the yoke 8 to which the coil bobbin 7 and the core 14 are fixed has been assembled on the base 12, the junction terminal 2a is connected to the coil lead connecting terminal 1 for external connection by, e.g., a welding method.
However, the above-described connecting methods involve the following problems. With the first method, the position of the end portions of the coil lead is not fixed, this renders the connection of the coil lead to the terminal portions of the base difficult, thereby making it very difficult to automatize the operation of connecting the end portions of the coil lead. With the second method, although each of the above-described connecting processes can be automatized relatively easily, the method requires junction terminals for the connection of the coil lead, and this leads to an increase in the number of the required component parts, hence, to an increase in production cost as well as in the number of the required connecting processes.